In the context of a medical emergency, a patient is often first treated in the field by a first responder, such as police or fire department personnel, and/or a paramedic, such as an advanced cardiac life support (ACLS) certified paramedic associated with a local emergency medical service (EMS). In the field, the patient may be diagnosed and/or treated using a medical device, such as an external defibrillator, which may include patient physiological monitoring capabilities. The patient may then be transported to a hospital or other treatment center for further and, in some cases, more elaborate and critical treatment. In general, it is desirable that such further treatment at the hospital be provided as quickly as possible.
For example, Acute Coronary Syndrome (ACS), which includes Acute Myocardial Infarction (AMI), is responsible for half of all deaths related cardiovascular disease. Approximately one third of patients with confirmed ACS are diagnosed with ST-segment Elevation Myocardial Infarction (STEMI). One type of treatment performed at a hospital for a patient diagnosed with STEMI is a procedure called Percutaneous Coronary Intervention (PCI), commonly known as coronary angioplasty. The procedure involves inserting a balloon catheter into a patient's clogged artery and expanding the balloon in an attempt to open up a passage for blood flow within the clogged artery. PCI can be an effective treatment for STEMI patients provided that the treatment is quickly delivered to the patient. The longer that the flow of blood to the heart is blocked, the higher the risk of serious damage to the heart muscle. Thus, reducing the time interval between onset of ACS and PCI treatment is critical to reducing the mortality rate for STEMI or other ACS patients.
In many cases, when a patient first begins to experience symptoms of ACS, several events must take place before PCI or some other critical in-hospital treatment can be administered to the patient. For example, the paramedics may be called and need to arrive at the scene. The patient may be monitored using an external defibrillator. This may involve acquiring and displaying an electrocardiogram (ECG), e.g., a 12-lead ECG, from the patient, and analyzing the results. Other physiological parameters of the patient, such as oxygen saturation, blood pressure, or carbon dioxide partial pressure, may be monitored with the defibrillator or one or more other medical devices.
The defibrillator may provide an indication that the patient is experiencing or suspected to be experiencing STEMI or some other AMI, or allow a user to make such a determination, based on analysis of the ECG. The defibrillator may also determine, or allow a user to determine, that the patient is experiencing an arrhythmia, such as ventricular fibrillation, based on the ECG If the patient is experiencing an arrhythmia, the defibrillator may deliver one or more electrical defibrillation shocks to terminate the arrhythmia.